In general, a magnetic recording medium such as a magnetic tape is produced by coating and drying a magnetic coating composition comprising a magnetic powder, a binder resin and other components on a support. In the case of a magnetic recording medium having only a single magnetic layer, it is necessary to cover a wide frequency band including low to high frequencies by means of the magnetic powder contained in the single layer. Since improvement in high frequency recording characteristic and noise reduction are demanded to increase recording density, magnetic powders having a high Hc value and a high BET value are used.
However, since conventional magnetic recording media are configured with a single magnetic layer and too much weight is laid upon high frequency characteristic, a magnetic powder having a high Hc value and a high BET value is used; therefore, the low frequency characteristic is unsatisfactory. Also, a magnetic powder having a high Hc value and a high BET value tends to fail to provide satisfactory output in Hi-Fi audio, whose the recording band is lower than that of video luminescence.
On the other hand, in the case of magnetic recording media for video use, there have been proposed media having a number of magnetic layers for the purpose of increasing magnetic recording capacity or improving magnetic recording characteristic in both the high frequency and low frequency bands of the medium to balance them (e.g., Japanese Patent Publication Open to Public Inspection Nos. 98803/1973, 172142/1984, 64901/1976, 56228/19833 and 146211/1988 and Japanese Patent Examined Publication Nos. 2218/1957 and 12937/1981).
However, even these media cannot serve well to increase all of chromatic output, video luminescence output and Hi-Fi audio output with a good balance and improve electromagnetic conversion characteristic in the entire frequency band covering high, moderate and low frequencies.